Section 140.430 - Wearing of work vests(a) Personnel dispatched from the vessel or that are working in an area on the exterior of the vessel without rails and guards must wear a lifejacket meeting requirements in 46 CFR 141.340 , an immersion suit meeting requirements in 46 CFR 141.350 , or a work vest approved by the Commandant under 46 CFR subpart 160.053. When worn at night, the work vest must be equipped with a light that meets the requirements of 46 CFR 141.340(g)(1) . Work vests may not be substituted for the lifejackets required by 46 CFR part 141.(b) Each storage container containing a work vest must be marked "WORK VEST".